Aluminum solder



Patented 5 1935 PATENT OFFICE ALUMINTUM SOLDER Friedrich Strasser,Basel, Switzerland N Drawing.

Application December 23, 1933,

fi'izal No. 703,849. In Germany December 30,

1 Claim.

For soldering aluminium solders are known which are composed of the fourcomponents aluminium-tin, zinc and silver. These solders were suitablefor some soldering purposes of 5 minor importance. If the pieces to besoldered were of large dimensions or if: these pieces were thick andespecially if the soldered parts were exposed to sea-water or saltcontaining air, these known solders gave no satisfaction. These knownsolders of aluminium, tin, zinc and silver are characterized by anexcess of tin and they were considerably too poor in aluminium. Theytherefore were solders of the tin character. The

contents of aluminium of this-known class of '15 solders was maximum onefifteenth-of the contents of zinc. V

The solder according to the invention is based on the discovery of theinventor, that the aluminium solders must contain mu more aluminao himand considerably less t to suit suchsoldering purposes, for which theknown'solders gave no satisfaction.

The inventor has found that the percentage of aluminium must be nearlyequal to the pergg centage of tin. 0f coursegi some diiferences in.

' the percentages above and-"below the indicated proportion; are allowedwithout altering the character of the new solder. The percentage of zincand silver together are to be chosen so nearly equal to the percentageof one of the components aluminium or tin, the percentage of silverbeing nearly the double of that of zinc.

The new solder is easily fusible and more fluid 35 and it oflers theadvantage over the known solders that in melting there is not the leastdevelopment of vapour or gas. a further very remarkable progress isoffered by the new solder in that, that the surface of the solder, which'40 is applied to the points to be soldered remains equally clean andfree from slags. A further valuable peculiarity-of the new solderconsists in its being suitable for-being molten again after beingapplied for the first time to the solder-' ing point, without forminggrains cr slags or I without being decomposed in its several metalcomponents. o 1 -ii V. This latter peculiarity permits that on thepoints to be soldered the solder may be molten several times, so that itcan be pointed along the points to be soldered. It is further possibleto apply the solder first on the points to be 10 soldered, then to coolthem and to heat them again and to unite the several layers to onesolder'adhering firmly and homogeneously together.

An example of the composition of the new Aluminium 39 Tin 33 Zino 11Silver 23 Here the number of parts ofaluminium is equal to the number ofparts of tin and the sum of the parts of zinc and silver is equal to the25 number of parts of one of the other components. l I This solderpresents a greater resistance against corrosion in salt-water, whatwould be very convenient for seacraft. In. a test in which the solderedpart was cooked for 96 hours at 90 centigrade in a solution of watercontaining 5 per cent of chloride of sodium, there were no cracks orbubbles to be observed and the weight was cent.

' I claim: I

An aluminium solder consisting of 33 parts of aluminium, 33 parts oftin, 11 parts of zinc and 23 parts of silver. 40

rammarcn STRASSER."

only increased for 0.13 per-

